Retro68/gcc/newlib/libc/machine/xscale/strchr.c

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2017-04-11 21:13:36 +00:00
#if defined __thumb__
#include "../../string/strchr.c"
#else
#include <string.h>
#include "xscale.h"
char *
strchr (const char *s, int c)
{
unsigned int c2;
asm (PRELOADSTR ("%0") : : "r" (s));
c &= 0xff;
#ifndef __OPTIMIZE_SIZE__
/* Skip unaligned part. */
if ((long)s & 3)
{
s--;
do
{
int c2 = *++s;
if (c2 == c)
return (char *)s;
if (c2 == '\0')
return 0;
}
while (((long)s & 3) != 0);
}
c2 = c + (c << 8);
c2 += c2 << 16;
/* Load two constants:
R6 = 0xfefefeff [ == ~(0x80808080 << 1) ]
R5 = 0x80808080 */
asm (PRELOADSTR ("%0") "\n\
mov r5, #0x80\n\
add r5, r5, #0x8000\n\
add r5, r5, r5, lsl #16\n\
mvn r6, r5, lsl #1\n\
\n\
sub %0, %0, #4\n\
0:\n\
ldr r1, [%0, #4]!\n\
" PRELOADSTR ("%0") "\n\
add r3, r1, r6\n\
bic r3, r3, r1\n\
ands r2, r3, r5\n\
bne 1f\n\
eor r2, r1, %1\n\
add r3, r2, r6\n\
bic r3, r3, r2\n\
ands r1, r3, r5\n\
beq 0b\n\
1:"
: "=&r" (s)
: "r" (c2), "0" (s)
: "r1", "r2", "r3", "r5", "r6", "cc");
#endif
while (*s && *s != c)
s++;
if (*s == c)
return (char *)s;
return NULL;
}
#endif